Sulfation reaction process of red mud and limestone were investigated by thermogravimetric analysis method.Phase composition of desulfurization product and calcined sample microstructure were examined by XRD,mercury i...Sulfation reaction process of red mud and limestone were investigated by thermogravimetric analysis method.Phase composition of desulfurization product and calcined sample microstructure were examined by XRD,mercury intrusion porosimeter and SEM respectively.Desulfurization mechanism of red mud was discussed,which provided useful data for red mud as substitute for limestone used for coal desulfurization agents.It is shown that the possible desulphurization index of red mud is higher than that of limestone under the same condition.Calcined red mud has more middling size pores and larger specific surface areas than calcined limestone,which enhances desulfurization reaction rate.Moreover,red mud includes more ferrite and alkali metal salt compared with limestone.At low temperature they can enhances lattice defect of desulfurization agents and the diffusion ability of Ca2+ and O2-.This improves speed of surface chemical reaction and final reaction.At high temperature ferrite and alkali metal may form fused mass with dicalcium silicate together.This reduces specific surface area and porosity of red mud,thus,desulfurization activeness of red mud is weakened.Alkali earth metal carbonate may be added when red mud is used for desulfurization agents in higher temperature boiler.展开更多
The microstructure of the raw,calcined,and desulfurized sa mp les of shell and limestone was detected and analyzed by SEM.Their ability of ca pturing SO2 was verified by using LCT-2 thermobalance and the high temperat...The microstructure of the raw,calcined,and desulfurized sa mp les of shell and limestone was detected and analyzed by SEM.Their ability of ca pturing SO2 was verified by using LCT-2 thermobalance and the high temperatur e tube reactor.The results showed that the better pore structure and smaller ga s diffusion resistance of shell were in favor of the inner reaction for SO2 ga s.Shell had higher calcium utilization ratio than that of limestone especially under the conditions of high reaction temperature and the increased reaction tim e.The bigger difference of the inner structure was found in the reaction of sul fation after calcination and direct sulfation.In direct sulfation, the reaction was restrained because of the bad pore connectivity, while the former reaction took place with good pore connectivity.展开更多
文摘Sulfation reaction process of red mud and limestone were investigated by thermogravimetric analysis method.Phase composition of desulfurization product and calcined sample microstructure were examined by XRD,mercury intrusion porosimeter and SEM respectively.Desulfurization mechanism of red mud was discussed,which provided useful data for red mud as substitute for limestone used for coal desulfurization agents.It is shown that the possible desulphurization index of red mud is higher than that of limestone under the same condition.Calcined red mud has more middling size pores and larger specific surface areas than calcined limestone,which enhances desulfurization reaction rate.Moreover,red mud includes more ferrite and alkali metal salt compared with limestone.At low temperature they can enhances lattice defect of desulfurization agents and the diffusion ability of Ca2+ and O2-.This improves speed of surface chemical reaction and final reaction.At high temperature ferrite and alkali metal may form fused mass with dicalcium silicate together.This reduces specific surface area and porosity of red mud,thus,desulfurization activeness of red mud is weakened.Alkali earth metal carbonate may be added when red mud is used for desulfurization agents in higher temperature boiler.
文摘The microstructure of the raw,calcined,and desulfurized sa mp les of shell and limestone was detected and analyzed by SEM.Their ability of ca pturing SO2 was verified by using LCT-2 thermobalance and the high temperatur e tube reactor.The results showed that the better pore structure and smaller ga s diffusion resistance of shell were in favor of the inner reaction for SO2 ga s.Shell had higher calcium utilization ratio than that of limestone especially under the conditions of high reaction temperature and the increased reaction tim e.The bigger difference of the inner structure was found in the reaction of sul fation after calcination and direct sulfation.In direct sulfation, the reaction was restrained because of the bad pore connectivity, while the former reaction took place with good pore connectivity.
